A New Cyclopoid Copepod (Chondracanthidae) Parasitic on the Armored Sea Robin from the Florida Straits

Abstract

Rhynchochondria longa gen. et sp. n. was found parasitic on the wall of the branchial chamber of the armored sea robin, Peristedion platycephalum (Goode and Bean), taken from the Florida Straits at a depth of 366 to 450 m. The new copepod differs from the known genera in the family Chondracanthidae in the female having a large, snoutlike rostrum and a trilobed swelling with a long middle process on the sternal area behind leg 1, and in both male and female having three pairs of biramous legs. The copepod is remarkable in having more than one dwarf male attached to the female. In the winter of 1965, while the author was making a general collection of parasitic copepods of marine fishes on board the R/V Oregon during Cruise 105, 12 female copepods were recovered from the branchial cavities of 12 armored sea robins, Peristedion platycephalum (Goode and Bean), caught with a 60-ft trawl net in the Florida Straits. Subsequent study of these copepods revealed that they represent a new genus and species of the family Chondlracanthidae. Two females and three males were dissected and examined in lactic acid, and the figures were drawn with the aid of a camera lucida. All measurements are in millimeters unless otherwise indicated. Genus Rhynchochondria gen. n. Female: Cephalosome fused with first pedigerous segment and separated from rest of body by a distinct neck. Rostrum snoutlike; another long process located immediately behind leg 1 on ventral surface of head. Second, third, and fourth pedigerous segments fused into a square trunk, bearing small, fused genital segment and abdomen at posterior end. Caudal ramus present. First antenna indistinctly 6-segmented; second antenna uncinate, with accessory antennule. Mandible falcate and denticulated; paragnath present; first maxilla a knob bearing four elements; second maxilla 2-segmented, terminal segment armed with strong teeth. Maxilliped 3-segmented, terminal segment unguiform. Legs 1 to 3 biramous, remi 2-segmented. Leg 4 absent. Legs 5 and 6 present. Male: Dwarf, attached to female by means of second antennae. Metamerism of body distinct, with single postgenital segment. Caudal ramus and cephalic appendages as in female. First three pairs of legs biramous, rami 2-segmented, except Received for publication 3 August 1966. * This study was done in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Boston University. 406 third endopod, where it is 1-segmented. Leg 4 absent. Legs 5 and 6 present. Type-species: Rhynchochondria longa sp. n. (Rhynchos = snout, chondria cartilage; longa -= long, alluding to the long sternal process and terminal seta on caudal ramus). Gender: Feminine. Rhynchochondria longa sp. n.